First Triple Crown winner in 37 years!

[Aroura]

I'm sure the humans get rich off of this.  Not so sure what the horse gets out of it.

Pretty certain the sort of traits bread into a race winning horse is not the sort of trait which would optimize the animal for surviving in the wild.   So perhaps the horse gets Darwinian extinction in the medium term out of it.

Someone not raised around horses I see.

In groups, human bread horses released into the wild actually do fine.  They have the same lifespan of wild horses.  Read up on it.

And horses are like dogs in some ways, they LOVE to be around humans.  These aren't wild animals like whales, here.  They have indeed been domesticated for thousands of years, they are natural social creatures, and if treated well, like a dog, are very loyal and loving to their human companions. 

Do you advocate we let all our dogs and cats go back into the wild as well?

Any animal can be treated cruelly by humans, but racehorses usually are not, or you don't get a very good racehorse.  And yes, after these 3 races, he'll get put out to stud, where he will get tons of sex and freedom for the rest of his life, as well as continued affection from his human caretakers, and probably die of old age somewhere around age 25, about 10 years older than a wild horse.  
Sounds DREADFUL.